Deposition Temperature Dependence of Optical Properties of a-Si:H for Short-wave Near-infrared Filter by DC Sputtering

Abstract Optical properties of refractory intermetallic thin films of Au 3 Zr were experimentally investigated for the first time, which show distinctive plasmonic properties in the visible and near infrared region. The films were fabricated through DC magnetron sputtering at various deposition temperature ranging from room temperature to 427°C and annealed at different vacuum levels. Both the structural and optical properties are found to be critically dependent on deposition temperature and anneal conditions. Films deposited between 205-320°C are shown to exhibit lower negative permittivity and better thermal stability, which could be linked to specific crystalline orientations. The films are stable when annealed at 10 -8 Torr, but are partially oxidized when annealed at 10 -6 Torr, suggesting oxidization could be a restricting issue for high-temperature applications in ambient environment.

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Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

10.26434/chemrxiv.7699358.v3 ◽

2019 ◽

Author(s):

Arundhati Deshmukh ◽

Danielle Koppel ◽

Chern Chuang ◽

Danielle Cadena ◽

Jianshu Cao ◽

...

Keyword(s):

Near Infrared ◽

Photophysical Properties ◽

Satellite Telemetry ◽

Transition Dipole Moment ◽

Short Wave ◽

Tissue Imaging ◽

Transition Dipole ◽

Deep Tissue Imaging ◽

Excitonic States ◽

Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 105 M-1cm-1). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

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Con_A-CNT (Carbon Nanotube) Conjugate with Short Wave Near-Infrared (SWIR) Laser Ablation for Tumor Therapy

10.21236/ada516380 ◽

2010 ◽

Author(s):

Huan-Yao Lei ◽

Ching-An Peng ◽

Ming-Jer Tang ◽

Harold Szu

Keyword(s):

Carbon Nanotube ◽

Laser Ablation ◽

Near Infrared ◽

Tumor Therapy ◽

Short Wave

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The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD

Micromachines ◽

10.3390/mi12060637 ◽

2021 ◽

Vol 12 (6) ◽

pp. 637

Author(s):

Hongliang Li ◽

Zewen Lin ◽

Yanqing Guo ◽

Jie Song ◽

Rui Huang ◽

...

Keyword(s):

Optical Properties ◽

Near Infrared ◽

Chemical Vapor ◽

Wide Bandgap ◽

Nonradiative Recombination ◽

Very High Frequency ◽

N Content ◽

High Frequency Plasma ◽

Frequency Plasma ◽

N Incorporation

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.

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Understanding Vine Hyperspectral Signature through Different Irrigation Plans: A First Step to Monitor Vineyard Water Status

Remote Sensing ◽

10.3390/rs13030536 ◽

2021 ◽

Vol 13 (3) ◽

pp. 536

Author(s):

Eve Laroche-Pinel ◽

Mohanad Albughdadi ◽

Sylvie Duthoit ◽

Véronique Chéret ◽

Jacques Rousseau ◽

...

Keyword(s):

Near Infrared ◽

Water Status ◽

Vegetation Indices ◽

Remote Sensing Data ◽

Short Wave ◽

Spatial And Temporal Scales ◽

Spectral Bands ◽

Main Challenge ◽

Spectral Scale ◽

Grape Varieties

The main challenge encountered by Mediterranean winegrowers is water management. Indeed, with climate change, drought events are becoming more intense each year, dragging the yield down. Moreover, the quality of the vineyards is affected and the level of alcohol increases. Remote sensing data are a potential solution to measure water status in vineyards. However, important questions are still open such as which spectral, spatial, and temporal scales are adapted to achieve the latter. This study aims at using hyperspectral measurements to investigate the spectral scale adapted to measure their water status. The final objective is to find out whether it would be possible to monitor the vine water status with the spectral bands available in multispectral satellites such as Sentinel-2. Four Mediterranean vine plots with three grape varieties and different water status management systems are considered for the analysis. Results show the main significant domains related to vine water status (Short Wave Infrared, Near Infrared, and Red-Edge) and the best vegetation indices that combine these domains. These results give some promising perspectives to monitor vine water status.

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The effect of the LC mixtures with the different clearing point on temperature dependence of the electro-optical properties of polymer dispersed liquid crystals

Molecular Crystals and Liquid Crystals ◽

10.1080/15421406.2021.1934641 ◽

2021 ◽

pp. 1-14

Author(s):

Huimin Zhang ◽

Fei Li ◽

Kexuan Li ◽

Yongming Zhang ◽

Yuxin Peng ◽

...

Keyword(s):

Optical Properties ◽

Liquid Crystals ◽

Temperature Dependence ◽

Polymer Dispersed Liquid Crystals ◽

Polymer Dispersed ◽

Clearing Point

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High performing flexible optoelectronic devices using thin films of topological insulator

Scientific Reports ◽

10.1038/s41598-020-80738-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Animesh Pandey ◽

Reena Yadav ◽

Mandeep Kaur ◽

Preetam Singh ◽

Anurag Gupta ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Nonlinear Optical ◽

Near Infrared ◽

Optoelectronic Devices ◽

Nonlinear Optical Properties ◽

Metallic Surface ◽

Strong Light ◽

High Performing ◽

Decay Times

AbstractTopological insulators (TIs) possess exciting nonlinear optical properties due to presence of metallic surface states with the Dirac fermions and are predicted as a promising material for broadspectral phodotection ranging from UV (ultraviolet) to deep IR (infrared) or terahertz range. The recent experimental reports demonstrating nonlinear optical properties are mostly carried out on non-flexible substrates and there is a huge demand for the fabrication of high performing flexible optoelectronic devices using new exotic materials due to their potential applications in wearable devices, communications, sensors, imaging etc. Here first time we integrate the thin films of TIs (Bi2Te3) with the flexible PET (polyethylene terephthalate) substrate and report the strong light absorption properties in these devices. Owing to small band gap material, evolving bulk and gapless surface state conduction, we observe high responsivity and detectivity at NIR (near infrared) wavelengths (39 A/W, 6.1 × 108 Jones for 1064 nm and 58 A/W, 6.1 × 108 Jones for 1550 nm). TIs based flexible devices show that photocurrent is linearly dependent on the incident laser power and applied bias voltage. Devices also show very fast response and decay times. Thus we believe that the superior optoelectronic properties reported here pave the way for making TIs based flexible optoelectronic devices.

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